This proposal for "Optoacoustic and Ultrasonic Imaging of Angiogenesis" combines optoacoustics and ultrasound in a single instrument for the first time. A I 2MHz phased array ultrasound probe equipped with fiber optics for delivery of laser illuminations will operate in the backwards mode. In this method the ultrasonic image and the optoacoustic image will be spatially overlaid and then fused in some presentations. The ultrasonic images will include B-Mode, color Flow Doppler, power Doppler and Spectral Doppler. A stacked transducer will double the acoustic spectral capabilities to 24 MHz on reception to attain visualization of very small vessels in the neovascuIarization. An OPO laser will provide a narrow wavelength from a spectrum of Infra Red wavelengths of light to photometrically select different compounds for light absorption, expansion and emission of ultrasound. Estimation of the oxy / deoxy hemoglobin in small vascular regions will be displayed as an image overlay. This unique instrument differentiates blood in optoacoustics, and tissue in ultrasound, allowing very high resolution of blood vessels, their flow (especially low flow without interference of wall motion) and their oxygen content. WinProbe's Scientific Research Platform will be optimized for this new combination of modalities and will produce fused images in real time. This proposal includes clinical studies to image and quantitatively access angiogenesis in mice under the effect of known anti-angiogenesis drugs. The goal is to commercialize an instrument for clinical research. The role of angiogenesis in cancer is well documented in the literature and this instrument can be expected to make a significant contribution to the science of cancer research. Future commercial products are expected to follow in endoscopic instruments to assist in the detection of cancer where optical assessments are limited to the surface and are contrast deprived.